Programmable auditory prosthesis with trainable automatic adaptation to acoustic conditions

Background

1. Field of the invention

The present invention relates to a programmable auditory prosthesis, such as a hearing aid or cochlear implant. In particular, the invention is an auditory prosthesis that adjusts its sound processing characteristics in a particular acoustic environment in a manner that is similar or identical to that previously determined by the user of the prosthesis as optimal for that environment.

2. Related art

Hearing loss, which may be due to many different causes, is generally of two types, conductive and sensorineural. Of these types, conductive hearing loss occurs where the normal mechanical pathways for sound to reach the hair cells in the cochlea are impeded, for example, by damage to the ossicles. Conductive hearing loss may often be helped by use of conventional hearing aid systems, which comprise a microphone, an amplifier and a receiver (miniature speaker) for amplifying detected sounds so that acoustic information does reach the cochlea and the hair cells. Since the elevation of the minimum detectable sound pressure level may vary with the frequency of an acoustic test stimulus, the amplifier may be preceded by, or comprise of, a bank of filters to enable different frequency components of the signal to be amplified by different amounts.

Sensorineural hearing loss occurs where the hair cells in the cochlea and the attached auditory nerve fibres are damaged or destroyed. Sensorineural hearing loss results in an increase in the minimum detectable sound pressure level, which often varies with the frequency of the test stimulus. However, in contrast to conductive hearing loss, the sound pressure level that is uncomfortably loud at a given test frequency is often approximately the same as for people with normal hearing. The result is a reduction in the dynamic range of sound pressure levels that are audible yet not uncomfortably loud with the impaired ear, and this dynamic range of the impaired ear may vary considerably with the frequency of the acoustic test stimulus. For this reason, sensorineural hearing loss is often treated with hearing aid systems that employ non-linear amplification to compress the dynamic range of common sounds towards the dynamic range of the impaired ear. Such systems may use a filter bank that is followed by a bank of compressive amplifiers, so that the dynamic range of the signal is reduced by an amount that is considered appropriate for the dynamic range of the impaired ear in each band.

In many people who are profoundly deaf, the reason for deafness is absence of, or destruction of, the hair cells in the cochlea which transduce acoustic signals into nerve impulses. These people are thus unable to derive suitable benefit from hearing aid systems, no matter how much the acoustic stimulus is amplified, because there is damage to or absence of the mechanism for nerve impulses to be generated from sound in the normal manner. It is for this purpose that cochlear implant systems have been developed. Such systems bypass the hair cells in the cochlea and directly deliver electrical stimulation to the auditory nerve fibres, thereby allowing the brain to perceive a hearing sensation resembling the natural hearing sensation normally delivered to the auditory nerve. U.S. Pat. No. 4,532,930, the contents of which are incorporated herein by reference, provides a description of one type of traditional cochlear implant system.

Cochlear implant systems have typically consisted of two essential components, an external component commonly referred to as a processor unit and an internal implanted component commonly referred to as a stimulator/receiver unit. Traditionally, both of these components have cooperated together to provide the sound sensation to a user.

The external component has traditionally consisted of a microphone for detecting sounds, such as speech and environmental sounds, a speech processor that converts the detected sounds, particularly speech, into a coded signal, a power source such as a battery, and an external transmitter coil.

The coded signal output by the speech processor is transmitted transcutaneously to the implanted stimulator/receiver unit situated within a recess of the temporal bone of the user. This transcutaneous transmission occurs via the external transmitter coil which is positioned to communicate with an implanted receiver coil provided with the stimulator/receiver unit. This communication serves two essential purposes, firstly to transcutaneously transmit the coded sound signal and secondly to provide power to the implanted stimulator/receiver unit. Conventionally, this link has been in the form of an RF link, but other such links have been proposed and implemented with varying degrees of success.

The implanted stimulator/receiver unit traditionally includes a receiver coil that receives the coded signal and power from the external processor component, and a stimulator that processes the coded signal and outputs a stimulation signal to an intracochlea electrode assembly which applies the electrical stimulation directly to the auditory nerve producing a hearing sensation corresponding to the original detected sound.

Different users of auditory prostheses require differing outputs from their prosthesis to suit their individual requirements. This is the case even when individual users may clinically be regarded as having identical hearing loss profiles, are utilising identical prostheses, and when exposed to essentially identical acoustic environments. Because of this, sound processing schemes for hearing aids and cochlear implants typically contain a number of parameters for which the values can be adjusted to suit the requirements of individual users. Examples of such parameters include the sensitivity to incoming sounds and the variation of the frequency response. Typically, the parameter values are selected either by the prosthesis user in everyday situations (eg. the sensitivity (volume), frequency response), or by the clinician at the time the prosthesis is fitted (eg. the baseline frequency response and the rate at which the frequency response and sensitivity vary as the input level varies).

In more recent times, there has been a trend to provide auditory prostheses with an increasing number of adjustable parameters that can or must be adjusted to optimise performance. This increase has, however, highlighted the problem that there does not always exist a reliable prescriptive method for selecting the optimum values for the individual user, particularly as some optimum values may vary among individuals who have hearing loss profiles that may clinically be regarded as identical. It is accordingly often necessary for the clinician to make adjustments to the prosthesis based on the user's reported experiences away from the clinic, and the need to return to the clinic for these adjustments can be time consuming and inefficient.

One example of a hearing aid that can receive the impressions of a hearing aid user and take these into consideration during operation is described in U.S. Pat. No. 5,604,812. This document describes a hearing aid that has a memory that can store so-called "unsharp inputs", or impressions of the hearing aid wearer about prevailing ambient conditions and/or the volume of the output of the hearing aid, prescribable algorithms, hearing loss data and hearing aid characteristic data. A fuzzy logic module uses this data and control signals from an input signal analysis unit to calculate the output setting parameters for the hearing aid. The behaviour rules of the fuzzy logic module and/or the prescribable algorithms are calculated from the data stored in the aid's memory by a neural network, with the neural network being typically implemented on a personal computer that is connected to the aid. A problem with such an aid is the complexity of the processing scheme and an undesirably large drain on the aid's power source, typically an on-board battery. Further to this, such an aid would require a large amount of clinical time to correctly "train", as the user does not have direct control over what is optimal, and "unsharp inputs" are used in the training of the aid rather than precise and direct inputs.

Another example of a hearing aid that can receive the preferences of a hearing aid user and take these into consideration is described in U.S. Pat. No. 6,035,050. Such an aid requires the user to identify their current listening environment by selecting one of a limited number of listening situations on a remote unit. Should the user find that their current listening situation does not readily fall within those provided for selection, the benefit of such a aid becomes greatly reduced. Further to this, some listening situations on the remote unit, such as "at work", may consist of a range of different acoustic environments and hence may not be acoustically well-defined. Thus, a neural network may not be able to reliably recognise such listening situations from an analysis of the microphone signal that, due to practical considerations such as memory limitations and the desirability of fast recognition of a change in listening situation, must be limited to a period of seconds or a few minutes. Therefore, after training it is possible that the neural network may misclassify a listening situation, especially in situations that are not acoustically well-defined, which can result in the application of amplification parameters that are unsuitable for the current listening situation. In such a device focus is placed on attempting to categorise specific acoustic environments, rather than measure the parameters of the environment and use these parameters directly in the processing scheme, as is the case with the present invention. Another disadvantage of this device is that a major lifestyle change, such as a new workplace that is acoustically different to the previous workplace, may require different amplification parameters and hence a return visit to the clinic.

Another example of a hearing aid that can receive the preferences of a hearing aid user and take these into consideration is described in U.S. Pat. No. 6,044,163. This document describes a hearing aid that is similar to the hearing aid described in U.S. Pat. No. 6,035,050. A major difference is that the neural network is not restricted to selection of sets of amplification parameters that are stored in a memory, but may directly set the value of individual amplification parameters. The disadvantages of the hearing aid described in this patent are similar to those of the hearing aid described in U.S. Pat. No. 6,035,050.

The present invention is adapted to providing users with an auditory prosthesis that is adaptable and can adjust its output to the user when that user is exposed to varying ambient acoustic environments.

Further, the present invention is adapted to providing users with an auditory prosthesis that can be `trained` by the individual user to adapt its output to the user's preference in listening conditions encountered away from a traditional clinical situation, thereby reducing the clinical time required to fit an optimise a prosthesis to the individual user.

Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.

Summary

According to a first aspect, there is disclosed an auditory prosthesis comprising:

a microphone for receiving sound and producing a microphone signal corresponding to the received sound;

an output device for providing audio signals in a form receivable by a user of the prosthesis;

sound processing means operable to receive the microphone signal and carry out processing operations on the microphone signal to produce an output signal in a form suitable to operate the output device, and

user control means;

wherein the processing means is operable in a first mode in which the processing operation comprises at least one variable processing factor which is adjustable by a user using the user control means to a corresponding setting which causes the output signal of the sound processing means to be adjusted according to the preference of the user in the current acoustic environment; and

wherein the sound processing means is simultaneously operable in a second mode in which at least one of the at least one variable processing factor(s) is automatically adjusted on the basis of one or more previously selected settings.

Preferably, the control means can be adjusted throughout a substantially continuous range of settings, with the preferred setting being used to calculate the one or more variable processing factors, which alter the processing operations applied to the microphone signal.

Preferably, the settings of the control means are related to one or more variable processing factors by defined mathematical relationships incorporating coefficients, and where the values of said coefficients are calculated to be those values that cause the variable processing factors to best approximate the variable processing factors that occurred as a result of previous settings of the control means.

In this invention, it will be appreciated that what is considered an optimal output signal by one user may not be considered an optimal signal by another user. The present invention ensures that the prosthesis operates in a manner that suits the requirements of the user for the acoustic environments that the user encounters rather than in some manner predetermined from clinical tests which may not replicate the type of acoustic environments to which the user is routinely or occasionally exposed, and which may not necessarily replicate the subjective reactions of users when in those environments.

Preferably, the data memory means stores data sets representative of the characteristics of at least one acoustic environment. Preferably the at least one variable processing factor is automatically adjusted on the basis of the acoustic environments in which at least one variable processing factor was selected.

In a first embodiment, the processing means may be adapted when operable in the first mode to offer two or more possible optimal settings of the variable processing factor for selection by the user. In this case, the user is preferably able to compare the operation of the prosthesis when operating in a particular acoustic environment when operating with each setting and then select from these the setting that is best for that particular environment. The setting of the variable processing factor that is selected by the user may then be stored in the data memory means, optionally with data indicative of the characteristics of the particular acoustic environment. This process may be repeatable so as to allow the processing means to monitor whether the user's preference for a particular setting of the variable processing factor changes with time or usage. In this way, the user effectively selects or votes for the best setting each time. By repeating the process, the number of selections or votes made by the user for each setting may be monitored to allow the prosthesis to select the optimal setting of the variable processing factor or optionally, the optimal setting of the variable processing factor for a particular environment.

In this embodiment, the user may alternate between listening with the offered settings by operating a control means, and can select or vote for a setting of the variable processing factor(s) by operating an indicator means. In one embodiment, the control means may comprise a switch or set of buttons that is actuable by the user, and the indicator means may comprise a switch or button that is actuable by the user.

In another embodiment, the processing operation of the processing means may be adjustable by the user when the processing means is in the first mode of operation. Rather than offering a discrete selection of possible optimal settings for selection by the user, in this embodiment, the user is able to adjust a control means throughout a substantially continuous range that allows the user to alter the variable processing factor(s) throughout a range of values, and thus alter the processing operation of the processing means. Once the user has adjusted the control means to a setting in the substantially continuous range that is considered by the user an optimal setting for a particular acoustic environment, the user may operate an indicator means, such as a switch or button, leading to storage of that setting and optionally, data indicative of the particular acoustic environment in the data memory means. Actuation of this indicator means may be taken by the processing means as indicating that the particular setting of the control means at that time is considered optimal by the user for the particular acoustic environment in which the user finds themself.

In this embodiment, the control means may comprise a rotary wheel control. The rotary wheel control may be mounted on the housing of the prosthesis or alternatively, may be mounted on a remote unit. The control means could also be in the form of a toggle switch or press buttons.

In the above embodiments, the indicator means may be mounted on a housing of the prosthesis. In another embodiment, the indicator means may be mounted on a remote unit.

In a preferred embodiment, the settings selected by the user as being optimal to that user for a plurality of acoustic environments may be stored in the data memory means and optionally, with data indicative of the characteristics of those particular acoustic environments. The processing means operates in the second mode, and may simultaneously be operable in the first mode for a defined period of time or can be considered as operating in the first mode every time the user adjusts the control means and selects what is considered a new optimal setting for that particular environment. In another embodiment, the prosthesis may have a defined training period in which the prosthesis may be operable in the first mode of operation. This period may be as long as the user wishes or optionally, the prosthesis may signal to the user when the training period is complete. In this case, the prosthesis may be adapted to indicate the training period is complete once there has been a particular pre-defined number of instances in which the user has not selected a setting which is substantially different to the setting already estimated by the prosthesis to be optimal.

In a preferred embodiment, the prosthesis may further comprise a sound analysis means. The sound analysis means preferably receives input signals from the microphone and monitors the acoustic environment of the prosthesis user. The sound analysis means preferably provides an output representative of the acoustic environment being monitored at that time.

In a further embodiment, the data memory means may comprise one or more data memory locations. In one embodiment, the data memory means may comprise five data memory locations. In this embodiment, the first data memory location may contain the audiometric data of the prosthesis user and/or individual data for one or more loudness models used by the prosthesis. The second data memory location may contain characteristic data about the hearing prosthesis. The third data memory location may comprise one or more equations used to predict the optimal processing operation of the processing means for an individual user in different acoustic environments. The fourth data memory location may store the optimal sound processing data as selected by the user of the prosthesis. This data may be ordered in different ways, such as sequentially or indexed according to the corresponding acoustic environment data supplied by the sound analysis means. The acoustic environment data that corresponds to the optimal sound processing data is optionally stored in the fifth data memory location. Other data memory means having differing numbers of memory locations may be envisaged.

In one embodiment, the fourth data memory location may store a predefined maximum number of sets of optimal sound processing data. In one embodiment, the memory location may store a maximum of 400 data sets. Other maximum numbers can, however, be envisaged. In one embodiment, the data processing means does not utilise all stored data sets but only a predefined number of most recently logged data sets. For example, the data processing means may only utilise the last 256 data sets when determining the optimal value of a variable processing factor. In one embodiment, the newest data set to be stored in the memory location can be stored instead of the oldest data set in the memory location. This first in first out storage system ensures only the most recently logged data is ever stored in the prosthesis at any one time. In another embodiment, older data cannot be overwritten such that once the memory location is full no further data sets can be logged by the prosthesis. In another embodiment, old data is preferably selectively overwritten by the newest sound processing data according to the acoustic environment in which the sound processing data was selected.

In a further embodiment, the prosthesis preferably further comprises a data processing means. The data processing means preferably receives the output of the sound analysis means. Based on the output of the sound analysis means, the data processing means can be adapted to calculate the loudness of sounds present at the microphone. In one embodiment, the data processing means can calculate the loudness of the sounds as they would appear to a person with normal hearing and/or to a person with a degree of hearing impairment. The data processing means can be adapted to calculate other acoustic and psychoacoustic measures of the sounds present at the microphone. The data processing means can use the acoustic and/or psychoacoustic measures as inputs to the one or more equations stored in the third data memory location which estimate the optimal sound processing operation of the sound processing means for the user in the acoustic environments represented by the sound analysis means.

The data processing means further preferably uses the hearing prosthesis characteristic data stored in the second data memory location and the optimal sound processor data generated by the equations to automatically and continuously determine the appropriate setting of the processing means to provide the optimal output signal for the user in the current acoustic environment being experienced by the user.

In a preferred embodiment, the processing means can include an amplifier means and a gain control means. In this case, the operation of the amplifier means is preferably adjustable when in the first mode to allow the user to optimise the gain at each or every frequency of the amplifier in a particular acoustic environment. Once optimised, the prosthesis operates in a second mode in which the amplification characteristics of the amplifier means automatically adjusts to the optimal level. That is, in such embodiments the variable processing factor is preferably the amplifier gain at each or every frequency.

In a preferred embodiment of the above aspects, the gain at each or every frequency of the amplifier means is calculated through use of an equation having a pre-defined form. In one form the equation can be: G.sub.i=a.sub.i+b.sub.i*max(L.sub.i,c.sub.i)+d.sub.i*(SNR.sub.i-SNR.sub.a- v)

where i=the frequency band number; G.sub.i=gain for band i; a.sub.i=trainable coefficient for band i; b.sub.i=trainable coefficient for band i; c.sub.i=trainable coefficient for band i; d.sub.i=trainable coefficient for band i; L.sub.i=sound pressure level at the microphone in band i; SNR.sub.i=signal to noise ratio in band i; and SNR.sub.av=average SNR in all bands.

Other forms of the equation with other acoustic or psychoacoustic parameters, such as higher-order moments of the spectrum of the signal and variations of these moments with time, or other statistical parameters or estimates of the acoustic signal or combinations of these parameters, and optionally with other additional coefficients, can calculate the gain or processing factors other than gain, such as the speed at which the prosthesis reacts to change in the acoustic environment, the choice of the equations used will depend upon the particular application desired, with such applications falling within the scope of the present invention.

In the above embodiment, trainable coefficients include a, b, c and d, which as a result leads to the amplifier gain G being a variable processing factor.

Thus, in embodiments of the invention, more than one variable processing factor of the processing means can be adjustable by the user using the control means or multiple control means. Similarly, more than one variable processing factor of the processing means can be automatically adjusted as appropriate to any acoustic environment. In this embodiment, the control means or multiple control means can allow the user to adjust one or more of the following example operations of the processor means:

(i) the volume of the output signal;

(ii) the gain of the output signal at particular frequencies relative to other frequencies, for example the mid frequency gain can be boosted or attenuated with respect to the low or high band frequencies of the output signal; and

(iii) a slope control where the low and high frequency band gains are adjusted in opposing directions while the mid band gain is unchanged.

In this embodiment, for each of the operations of the processor means the user can select a setting which is optimal for each variable processing factor for the particular acoustic environment that they are in by actuating the indicator means. On multiple operations of the control means the user may select a setting which is optimal for one or more variable processing factors for the acoustic environment that the user experiences by actuating the indicator means. Thus, more than one operation of the sound processor means, as well as more than one variable processing factor, can be adjusted in combination for each vote or selection. Each time the indicator means is actuated, the gain in each frequency band is preferably recorded along with a data set indicative of the acoustic environment detected by the microphone. This data can be used with previous sets of data by the data processing means to calculate the gain equation coefficients that best match the logged training data in each band. The recorded gain in each frequency band may be used to calculate the gain equation coefficients.

In a further embodiment, when operating in the first mode the data processing means preferably does not calculate optimal gain equation coefficients until a predetermined number of selections have been made by the user. In one embodiment, the prosthesis can be adapted to not calculate optimal gain equation coefficients until at least fifty selections have been made by the user. In this case, where the predetermined number of selections have not been made, the processing means may when operating in the second mode preferably automatically calculate the output appropriate to the current environment, based on predetermined coefficients and/or variable processing factors. Once the predetermined number of selections have been made, the processing means may calculate the optimal gain equation coefficients on the basis of previous user preferences when in the first mode of operation, and automatically and continuously calculate the variable processing factors with these equations when in the second mode of operation. In another embodiment, the data processing means preferably does not wait for a predetermined number of selections to be made by the user before calculating the optimal gain equation coefficients, but preferably does not use the calculated coefficients when in the second mode of operation until the variable processing factors that are preferred by the user can be predicted with the equations and calculated coefficients with a certain degree of accuracy.

In an alternative embodiment, equations may not be used to determine the optimal variable processing factors for different environments. The optimally adjusted variable processing factors may be stored in the fourth data memory at locations determined by the corresponding acoustic environment data supplied by the sound analysis means. Prior to the commencement of operation in the first mode, the memory locations are preferably loaded with processing factors that are derived from empirical observations or prescriptive procedures for the corresponding acoustic environment parameter values. When operating in the first mode the optimally adjusted processing factor(s) may be stored in the fourth data memory at locations determined by the acoustic environment data. The optimally adjusted processing data may simply overwrite the prescribed data, or may be combined with old data written to the same location using a mathematical and/or statistical procedure. When operating in the second mode, the data supplied by the sound analysis means may be used to index the fourth data memory location, and the value(s) stored at the indexed memory location are preferably used to set the target value(s) of the corresponding processing factor(s) for the sound processing means. The processing factor(s) applied in the sound processing means may slowly converge towards the target value(s) to avoid the possibility of undesirable acoustic effects associated with excessively rapid or instantaneous changes of the applied value(s). This alternative embodiment eliminates the need for the fifth data memory location and the equations stored in the third data memory location, and hence the variation of a processing factor with the acoustic environment is not restricted by the relationships that are predefined in the equations.

In another alternative embodiment, the optimally adjusted variable processing factor(s) may be stored in the fourth data memory location and a mathematical and/or statistical procedure is used to calculate the optimal value of the processing factor(s). This alternative embodiment eliminates the need for the equations stored in the third data memory location, and the storage of acoustic environment data either directly in the fifth data memory location or to index setting data in the fourth data memory location. This alternative embodiment is an appropriate simplification for processing factors that do not vary with the acoustic environment, such as the maximum permissible level of the output of a hearing aid or cochlear implant before the output is uncomfortably loud.

In a further embodiment, the user can train the prosthesis to provide optimal variable processing factors for different listening criteria, such as to maximise speech intelligibility, listening comfort, or pleasantness. In one embodiment, an equation similar in form to equation 1 can comprise acoustic environment or psychoacoustic parameters that are highly correlated to a particular listening criterion, such as maximising speech intelligibility or listening comfort. When operable in the second mode the variable processing factors may automatically adapt for the predicted weighted combination of listening criteria as determined by the values of the coefficients and the acoustic environment and/or psychoacoustic parameters used by the equations.

In another embodiment, while operable in the first mode the user may indicate the listening criterion or combination of criteria used to determine the preferred adjustment of the variable processing factor(s) with an indicator means, or optionally the aid automatically predicts the listening criterion or combination of criteria from the values of acoustic environment and/or psychoacoustic parameters that are known to correlate with different listening criteria, and/or from the presence of signals of interest such as speech and music as detected by the prosthesis. The fourth data memory location may be divided into sections for different listening criteria, and the optimally adjusted variable processing factor(s) may be stored in a memory location(s) as determined by the listening criterion or combination of listening criteria under which they were adjusted by the user. The fifth data memory location is optionally also divided into sections for each different listening criterion for the storage of the acoustic or psychoacoustic parameter values that correspond to the values stored in the fourth data memory location. With this structure, the data in each section of the fourth and fifth data memory locations is preferably used to calculate the optimal coefficients of variable processing factor equations similar in form to equation 1 for each listening criterion. When operable in the second mode, the user can indicate the current listening criterion or combination or criteria via an indicator means or alternatively, the listening criterion or weighted combination of criteria can be predicted from the values of acoustic environment and/or psychoacoustic parameters that are known to correlate with different listening criteria and/or the presence of signals of interest such as speech and/or music, or by one or more trainable listening criteria equations that have acoustic environment or psychoacoustic parameters as their input, where the optimal coefficients of each listening criterion equation are calculated from the data stored in the corresponding sections of the fourth and fifth data memory locations. Once the listening criterion or weighted combination of listening criteria are either indicated by the user or automatically predicted by the prosthesis, the optimal variable processing factors may be calculated with equations similar in form to equation 1 for each criterion, and are combined according to the indicated or predicted weighting of the listening criteria.

In an alternative embodiment, when operable in the first mode the listening criterion or combination of criteria indicated by the user via an indicator means or predicted by the prosthesis may be used in addition to the corresponding acoustic environment and/or psychoacoustic parameters to index the location in the fourth data memory where the optimally adjusted variable processing factor(s) are stored. When operable in the second mode, the current values of acoustic environment and/or psychoacoustic parameters and the indicated and/or predicted listening criterion or combination or criteria may be used to index the fourth data memory location to retrieve the optimal variable processing factor(s) for the prevailing conditions. In another embodiment, the listening criterion or combination of criteria may not be used to index the fourth data memory location, and the processing factor value(s) stored at each location in the fourth data memory when operable in the first mode may be modified according to the weighted combination of listening criteria for the particular acoustic environment.

In the above embodiments, the listening criterion or combination of criteria is indicated by the user by an indicator means, such as a switch, toggle switch, or set of pushbuttons on the housing of the prosthesis, or alternatively on a remote unit.

According to a second aspect, the present invention provides an auditory prosthesis comprising:

a microphone which receives sound and produces an output signal corresponding to the received sound;

an output device that provides audio signals in a form receivable by a user of the prosthesis;

a sound processing means operable to receive the microphone signal and carry out a processing operation on the microphone signal to produce an output signal in a form suitable to operate the output device, wherein the processing means is operable in a first mode in which the processing operation comprises at least one variable processing factor which is adjustable by a user to a setting which causes the output signal of the processing means to be adjusted according to the preference of the user for the characteristics of the current acoustic environment;

a sound analysis means that also receives the microphone signal and outputs a data set representative of the acoustic environment;

a data memory means for storing a plurality of said user adjusted settings; and

a data processing means that analyses said stored settings and is operable to output control signals to the sound processing means;

wherein, upon receiving control signals from the data processing means, the sound processing means is simultaneously operable in a second mode in which said at least one variable processing factor is automatically adjusted on the basis of the previously adjusted variable processing factor selected by the user.

In this aspect, the features of the prosthesis can have the features as described above with reference to the first aspect where such features are compatible with the operation of the prosthesis as described therein.

In this aspect, the hearing prosthesis preferably uses the data memory means to store a record of optimal settings as determined by the user of the prosthesis for different acoustic environments. This record is then used by the data processing means to calculate coefficients of one or more equations that are used to predict the optimal setting of the processing operation of the speech processor for that user when exposed to a different acoustic environment.

In one embodiment, the hearing prosthesis can be adapted to output audio signals to a single ear of the user. In another embodiment, the hearing prosthesis can be adapted to output audio signals to both ears of the user. In yet a further embodiment, signals from the inputs of two prosthesis can be connected to the sound analysis means by wire or wirelessly. The control means for the above embodiments can be located on the housing of each prosthesis, a remote unit for each prosthesis, or the control means for both prostheses can be located on a common remote unit.

In one embodiment of the above aspects, the hearing prosthesis can be a hearing aid. In this embodiment, the output device of the hearing aid can be an earphone that receives the output signal of the processing means and generates amplified sounds that are delivered into the ear of the user.

In another embodiment, the hearing prosthesis can be an implanted hearing aid device whereby the output device of the prosthesis can be a vibrating mechanism, mechanically coupled to the middle or inner ear.

The description continues in the full USPTO document.